Test kubernetes service account in helm chart

[mathew-fleisch]

The helm chart has a flag to toggle giving the pod a kubernetes service account, but there are no tests to prove it works as expected/intended. A pod should be able to run kubectl commands on the local cluster if enabled, and a pod should reject/error kubectl commands when disabled. These two tests would require a secondary deployment to test no-service-account, because the default deployment includes one.

https://github.com/mathew-fleisch/bashbot/blob/f16c935485e84ec427caf4368000a4a2f5bb263b/charts/bashbot/values.yaml#L25-L31

https://github.com/mathew-fleisch/bashbot/blob/f16c935485e84ec427caf4368000a4a2f5bb263b/charts/bashbot/values.yaml#L25-L31